Information that describes electronic device users is increasingly tracked. Not only are user demographics, such as the user's age, gender, race, household income, and so on, tracked, but user interactions with content the users consume are also tracked, e.g., selections made or actions taken on a website, selections made to view content, online purchases made, amount of time spent on websites, amount of time spent playing video games, and so on. In some cases, this information can be tracked across multiple devices, resulting in information that describes a substantial portion of a user's activity with electronic devices. Tracking this information enables entities, such as advertisers, to target content to users having certain demographics and who undertake certain activities.
Despite the variety of information available for targeting content to users, efforts to improve such targeting continue, e.g., by changing or adding to the information that is tracked about users and then used to target content to them. For particular types of content, some user interactions are tracked while others are not. Consequently, conventional techniques for targeting content to users are limited by the information tracked.